Place all ingredients for marinade in a blender container, except for olive oil and puree until smooth and consistent throughout. While blender is running, slowly add all of the olive oil in a steady stream until emulsified in the marinade.

Place mushrooms in a large glass baking dish, pour marinade over mushrooms and marinate for 2 hours in a refrigerator.

In a large bowl, toss yellow tomatoes with 2 teaspoons olive oil, salt and pepper. Spread on a cookie sheet and roast in oven for 35 to 40 minutes, or until golden-brown in color.

In a small sauté pan combine garlic, onion and 1 teaspoon olive oil and sauté until onions are translucent.

Place roasted tomatoes, sautéed onions and garlic, basil, cane sugar and lemon juice in a food processor and puree until smooth.

Combine all ingredients for relish in a small saucepot over medium-high heat and simmer until liquid has evaporated.

Remove mushrooms from marinade and discard excess marinade. Place on baking sheet and roast for 5 to 10 minutes, or until mushroom is soft. Serve 2 mushrooms with 2 tablespoons tomato puree and 1 tablespoon bell pepper relish.